The Lowest of the Ionized Layers of the Upper Atmosphere

The “Stockwerk-Gliederung” of the Earth’s atmosphere introduced by PENNDORF and FLOHN is a promising method to describe the different atmospheric regions from the nearest to the ground up to the highest levels. The region above the upper inversion (at ca. 75 km) up to 100 km height is generally called the D-layer which means the lowest of the ionized regions in the upper atmosphere of the Earth.

The behaviour of the D-layer, its most reasonable theory of formation, and its function with regard to the propagation of electromagnetic waves are discussed. Features related to solar-terrestrial phenomena are shown. Theories and ideas by various authors are compared with each other.

The complete investigation from which this paper gives an extract is being published elsewhere.